Reciprocating piston engines are well known in the prior art, the most common having a rotating crankshaft with off-set eccentric surfaces to which the pistons are connected for their reciprocation. Usually, there is a piston rod for each piston that connects the piston to the eccentric surface. This arrangement is commonly found in the well known V-8, straight 6 and 4 cylinder engines used in automobiles and boats. There are also the usual camshafts and valves, spark plugs and an ignition system. One of the problems with this arrangement is that the engines mentioned require the size of the engine block to be long enough to handle at least four pistons in a line. Considering that a single piston is about three inches or more in diameter, when multiplied by four and then adding in the cylinder size plus a cooling jacket surrounding each cylinder, the block will measure twenty inches or more. Engines of this size take a lot of space in an engine compartment.
Also, the conventional V-8 and straight 6 and 4 cylinder engines have been inefficient for their size and weight.
It is also known that rotary engines use radial placement of the pistons around a crankshaft with eccentric surfaces, require less space, and have fewer moving parts. Commonly, the pistons are connected to the crankshaft by piston rods. This type of engine does not require long crankshafts since there are generally four pistons radiating from the crankshaft and in the same plane. Most rotary engines have four pistons positioned 90 degrees apart, and a few have more. There are a few fluid motors which have two banks of four pistons stacked and connected to the same crankshaft. Two examples of this stacked arrangement are shown in U.S. Pat. Nos. 1,488,528 and 2,709,422. When pistons are arranged in a radial pattern and are 90 degrees apart, the pistons 180 degrees apart are often referred to as opposed pistons.
One of the difficulties with radial or opposed piston engines is providing an intake valve system to supply an air or a fuel/air mixture to the cylinders as needed. The usual intake valve and manifold arrangement with a camshaft to open and close the intake valves does not appear to be the answer, since the valves would have to be mounted on each head along with an overhead cam, adding substantially to the engine size and weight. One valve system of interest is shown in U.S. Pat. No. 3,584,610, where the intake valves extend coaxially through the pistons and includes valve stems carrying slotted guides and tension springs. A lobed cam moves the piston and intake valve against the valve closing force of the spring to open the valve to admit ignition gases to the combustion chamber. A similar type of piston with an intake valve is shown in U.S. Pat. Nos. 1,010,754 and 1,580,720. In the patents cited, the fuel or fuel/air mixture are pumped into the crankcase where the crankshafts and other moving parts are located. Such a crankcase design does not provide proper lubrication of these moving parts, where high revolutions require the shaft bearings and the reciprocating pistons to be well lubricated to reduce wear. To avoid the use of overhead cams, rocker arms, etc., which make up the well known assembly or the intake valve-in piston arrangement with poor crankcase lubrication, a different valve system is needed. The present invention addresses this need.